No, you get a choice of which product you want to use. If you ring and place a bet with a bookie, they'll usually ask how you want the bet to be placed (if they offer more than one way).

You can accept the fixed price they quote about a horse then and there (markets are usually opened about 20 minutes before each race) or you can choose to bet at TAB odds on any tote (not available with all bookies) or as with Sportingbet you can choose best odds which gives you the higher price of SP or TAB at the jump.

If you want to bet top fluc, you have to place your bet before noon (with Sportingbet or IAS etc).

But you have to nominate how your bet is to be wagered.

IAS have different products which have been discussed by others in different posts.

Cheers